Download Burp, Rumble, Toot

Burp, Rumble, Toot! How your lunch can turn
you into a one-person band by Karen Barrow
You gulp a can of soda, and a few minutes later ... BURP! You feel hungry,
and hear a noise from your stomach ... GRUMBLE! You eat the cafeteria's
spicy bean dip, and ... well, you know what happens.
"You may laugh, but everyone's body makes noise," says David Sachar, a
gastroenterologist, or doctor of the stomach and intestines, at Mount Sinai
School of Medicine in New York City.
And even though your body's orchestra may make funny sounds, the noise is a
sign that your gastrointestinal system (body system that breaks down food for use) is doing its job-digesting food and getting rid of waste (see Nuts & Bolts, p. 17). That's because behind all the rumbles
and toots is one ingredient your body doesn't need: gas.
Lets take a tour of your insides to find out where all the gas comes from, and why it leaves in such
noisy ways.
EATING AIR
It's lunchtime. You and your friends are munching on sandwiches and chips, laughing about the corny
joke your science teacher told today. But along with the turkey on rye, something else is sliding down
your throat that will exit later as a gassy burst: "Burps are mostly swallowed air," says Sachar.
Drinking bubbly drinks, talking, chewing gum, and eating too quickly can cause you to swallow a lot
of air. That air gets pushed down your esophagus (eh-SAH-fah-gus), a tube that connects your throat to
your stomach. The air fills your stomach and, soon, there's no room left in your blown-up tummy. How
to get rid of the air? Some of it gels squeezed back out of your mouth, causing eructation (ih-rehkTAY-shun), a fancy word for burping.
No matter how hard you may try, it's tough to muffle the noise. That's because when you eat, a tiny
flap of tissue, called the epiglottis (eh-pih-GLAH-tis), flops over to cover your windpipe and prevent
swallowed food from traveling into your lungs. Between bites, the tissue flops back over your
esophagus to let you breathe. As a burp is born, the air pushes past the epiglottis. This causes the flap
to vibrate and move the air in your throat, creating sound waves. These vibrating energy waves give a
burp its noisy blast.
Even if you avoid soda and put the gum away, the occasional burp will surely still slip by. Just be sure
to cover your mouth to be polite.
RUMBLE IN YOUR TUMMY
Lunch was great, but by the time 3 p.m. hits, all you can think about is an after-school snack. You hear
a grumble from below reminding you that it's lime to eat. Turns out, those gurgles don't really come
from your stomach.
Inside your stomach, chemicals called enzymes break down your food into its smallest parts, called
nutrients. These enzymes can't completely digest all your food. So after about four hours of sitting in
your stomach, the leftover, partially digested mush moves on to the small intestine, where even more
digestion will take place.
The small intestine is a snaking, narrow tube roughly 6 meters (20 feet) long. To shuttle the mush
through this tube, muscles around the intestine ripple with wavelike contractions, called peristalsis
(per-eh-STAHL-sehs). As the slushy food and leftover gas squish through the intestines, you may hear
grumbles called borborygmi (bor-buh-RIG-my).
Even if your intestines are talking, you don't need to grab a snack right away. The gurgles and
grumbles are just signals that your stomach has emptied enough to make room for the next meal. "It is
just your body telling you that it's ready for food," says Sachar.
A MIGHTY WIND
So far, the sounds of gas have been echoing throughout your digestive system. But there's more to
come!
Inside your large intestine are trillions of microbes. For these tiny organisms, the leftover food that
survived the trip through your stomach and small intestine is an all-you-can-eat buffet. The microbes
contain specialized enzymes that are able to break down and digest the remaining food. They
metabolize some of the nutrients, converting them into the energy they need to grow.
However, as the microbes feast, they produce waste in the form of--you guessed it--gas. The gas builds
up and pushes through the rest of your intestine. Then, out of your body it goes--toot!
MEGABLAST
Foods like beans, broccoli, and milk products are especially hard for your stomach and small intestine
to digest. That's because they are made of tough sugar molecules, or particles of two or more atoms
joined together. Foods with these compounds make it to your large intestine without breaking down
much.
So when you eat a bean burrito topped with extra cheese, the microbes get a supersizered meal. The
extra gas they produce powers through your large intestine, causing more flatulence (FLA-chuh-lense)
than usual. "The stronger the wind, the louder the result," says Alan Baird, a physiologist (scientist
who studies the body's vital functions) at the University College Dublin in Ireland.
The gas you blast is a combination of nitrogen, oxygen, carbon dioxide, hydrogen, and methane--the
same gases that make up the air you breathe. So why does your released gas sometimes smell? When
certain types of foods are digested, they produce a tiny amount of hydrogen sulfide, the same gas that
gives rotten eggs their stinky scent.
PARDON ME
There is very little you can do to prevent gas. No matter what, you will pass gas approximately 14
times a day. And you'll burp a couple of times too.
Yes, body noises can be embarrassing. But your gastrointestinal system can't function without them.
Just be sure that when a little gas does sneak past, you say, "excuse me." Then, thank your body for a
job well done!